I couldn't forgive him or like him, but I saw that what he had done was, to him, entirely justified. It was all very careless and confused.

The Carelessness of the Upper Class
Tom’s blaming Myrtle’s death on Gatsby when he didn’t know the entire picture (Daisy actually ran her over) demonstrates his tendency towards putting those he deems inferior in harm’s way. He acts irrationally and allows his vision of Gatsby as a good-for-nothing, new money man to cloud his judgement. He puts a deliberate barrier between himself and Gatsby, between old money and new money. He almost treats Gatsby as someone from a different species–a different race. He does not even feel remotely bad about directly causing Gatsby’s death, as though he were just squashing a bug.